This study examined the relationship of type of sexually instigating situation (partner behavior conveying emotional investment or not), relationship stage, and gender to self-reported likelihood of engaging in sexual behavior. Participants (200 female and 122 male college students) read scenarios describing partner behavior in eight hypothetical sexual situations. Five of the sexual situations were proposed to explicitly communicate a sense of emotional investment in the relationship, and three other scenarios were conceived as not explicitly conveying emotional investment. Emotional investment situations were hypothesized to influence likelihood ratings as a function of imagined relationship stage (dating or in a serious relationship), manipulated across participants. Situations not conveying investment were hypothesized to influence ratings as a function of both relationship stage and gender. In large part, hypotheses were confirmed. The few exceptions were consistent with other gender-role considerations related to trust and power.